Outlook and mobile clients don’t authenticate after November 2021 fixes for Windows installed
n a Microsoft Exchange Server 2019, 2016, 2013, or 2010 on-premises environment that’s configured to use Kerberos for authentication, the Microsoft Outlook and mobile device clients continually prompt for authentication after you install the November 2021 Windows Server update on domain controllers to fix the problem that’s described in security advisory CVE-2021-42278.
An out-of-band Windows update is available to resolve this problem. Install the following fix on domain controllers, as appropriate for your system version.
|OS||Resolving KB article|
|Windows 10, version 1809Windows Server 2019||5008602|
|Windows 10, version 1607Windows Server 2016||5008601|
|Windows Server 2012 R2||5008603|
|Windows Server 2012||5008604|
|Windows Server 2008 R2||5008605|
|Windows Server 2008||5008606|